Once they own Mint, Mint just becomes their lowest tier plan. You can keep moving the lowest tier price up to the point the standard T-mobile package becomes attractive.
Mint no longer works independently in applying pricing pressure. The pressure that made T-mobile even buy Mint (however little pressure) is now gone.
That only works in the real world if there is zero competition.
This becomes virtually true regionally I think. I believe you that there are 100s of MVNOs, but I only saw Boost and Mint within my area physically. Now one is gone.
I’m still in an area where I have two options for Internet, one of which is on top of the other’s infrastructure. There are hundreds of ISPs nationwide, I’m sure, but not in my area.
Buying out under-cutters and re-listing the service at the price you prefer is a crude and simple strategy and can only really be done by the largest players.
In the US, MVNOs are happy to sell you service nationwide. All of them resell services that are ultimately provided by one (or more) of the big 3 carriers.
It is completely dissimilar from the hardwired ISP market, wherein: With MVNOs, choice absolutely abounds, and there is competition a'plenty.
How much competition would Mint Mobile actually be for T-mobile?